44、k8s-数据存储-配置存储-configMap-（用于存储配置信息的）

概念：ConfigMap是一种比较特殊的存储卷、它主要的作用是用来存储配置信息的
其模板如下:
1、创建配置卷的yaml文件：vim configmap.yaml
-------------------------------------------------------
apiVersion: v1
kind: ConfigMap
metadata:
  name: configmap
  namespace: dev
data:                    #数据由键值对组成
  info:                #key
     username:admin    #volume
      password:123456
-------------------------------------
2、创建：kubectl create -f configmap.yaml
3、查看：kubectl describe cm -ndev
--------------------------------------------------------------
Name:         configmap
Namespace:    dev
Labels:       <none>
Annotations:  <none>

Data
====
info:                #键
----
username:admin password:123456        #值
Events:  <none>
----------------------------------------------------------------------
4、将这个配置信息configMap挂载到pod里去：
    ·创建pod.yaml：vim pod-configmap.yaml
------------------------------------------------------------------------------------------
apiVersion: v1
kind: Pod
metadata:
  name: pod-configmap
  namespace: dev
spec:
  containers:
  - name: nginx
    image: nginx:1.17.1
    volumeMounts:       
    - name: config        #要挂载到哪一个卷类型的名字、要与本机挂载的卷名要一致
      mountPath: /configmap/config        #将容器中的/configmap/config 目录挂载到本机的 configMap 配置卷上（进入容器中会有这个目录）
      
  volumes:          #引用configmap
  - name: config
    configMap:                #卷类型
      name: configmap        #注意这个名字要和上面创建的configMap的名字要一致、表示使用以这个名字命名的卷
-------------------------------------------------------------------------------------------------------------
5、创建pod：kubectl create -f pod-configmap.yaml
6、查看pod：kubectl get pod pod-configmap -ndev
-----------------------------------------------------------------
NAME            READY   STATUS    RESTARTS   AGE
pod-configmap   1/1     Running   0          34s
----------------------------------------------------------------
7、进入pod： kubectl exec -it pod-configmap -ndev /bin/sh
    ·进到挂载的目录下：# cd /configmap/config
    ·查看：
    -------------------------------------------------------------------------
    [root@master-1 home]# kubectl exec -it pod-configmap -ndev /bin/sh
    # cd /configmap/config
    # ls
    info
    # more info
    username:admin password:123456        #这个就是第一步创建的configMap是配置的信息、说明将configmap挂载到了容器内了
    ---------------------------------------------------------------------------------------------------------------
8、configMap还支持信息的动态更新
    ·编辑configMap的信息：kubectl edit configmap configmap -n dev
    ·将password改为1234567890
    --------------------------------------------------------------------
    apiVersion: v1
    data:
      info: username:admin password:1234567890
    kind: ConfigMap
-----------------------------------------------------------------------
    ·在进入容器中查看：kubectl exec -it pod-configmap -ndev /bin/sh
    -----------------------------------------------------------------
    # cd /configmap/config
    # ls
    info
    # more info
    username:admin password:1234567890
    ---------------------------------------------------------------------